The end of the world is nigh... not quite but certainly the end of Mad Men on television.

Like other long-running shows, Breaking Bad, The Sopranos, The West Wing, The Thick of It, Sex in the City and The Wire , the end is coming and many viewers will mourn.

Unlike those other shows Mad Men is drip-feeding the final series. The seventh episode and final for this year will air in New Zealand next Sunday. In 2015, a further seven episodes await. Then that will be it.

When the end comes, some will turn their phones off to make sure they are not disrupted by the uninitiated. Others will save the last episode for a specific night in or invite friends over and make a party of it. It will be a TV event.

The dapper yet flawed Donald Draper will no longer grace our screens, we won't get to hate Betty and Pete any more and Joan's sultry curves and wiggle will be committed to the hard drive or video cabinet.

That sense of loss will be there for many of us.

One of Australia's most watched video bloggers, Natalie Tran of Sydney used her channel this week to describe her pain at the imminent demise of Mad Men.

"The credits roll up, everything that once mattered to me matters no more," Tran tells her viewers.

Her tongue-in-cheek monologue talks about her "super emotional" response to the end of a series - wearing dark clothes, crying at the memories, looking at photos of the lost show.

The phenomena of impending mourning at the end of a long-running television show is becoming more pronounced, said Dr Brian Morris, a senior lecturer in media at RMIT University.

"A satisfying ending to a great series can certainly deliver an emotional high," Morris said.

But when it is over and if there is nothing to go on with, it can bring about a low.

Morris said the network hype and build up to a series finale makes the end sometimes difficult to accept, but it was often cathartic.

"Reaching that special point where it is actually a relief and you think: 'Wow - what a journey' and then you have to go and do something mundane," Morris said.

"At the end of each season - of say The Wire - there is a sense of catharsis but when the show finishes that is the end," he said.

Not only did viewers invest hours of their lives watching TV but fans of these shows could spend hours on the internet digging deeper into characters, looking at fan forums and reading about the makers and actors, Morris said. Many people invested much of themselves in shows, leading to a sense of loss when it finished.

While the end of a series might come, Dr Morris said good television could be enjoyed over again and again. He professed to have watched The Wire's five seasons up to four times.

"I think TV now is like reading a good novel and then going back in four years time and re-reading it and you get the same level of pleasure from it. I think good TV is so rich and multi-layered now that you can revisit it much more easily," he said.

"These long form shows are so dense and rich that they will continue to be watched over again, although you will always know what happens in the end," he said.